Tappet



S. JENCICK June 4, 1935.

TAPPET R k m m E Md W Wu H k A n ,m e If a 9 5 Patented June 4, 1935uurrso STATES PATENTOFFICE Stephen Jencick, Chagrin Falls, OhioApplication November 25, 1931, Serial No. 577,354

5 Claims.

This invention relates to an improved form of tappet for use in aninternal combustion engine.

As is well known to those who are familiar with the art to which thepresentinvention re- 5 lates, each cylinder of aninternal combustionengine is provided with intakeand exhaust valves which are normallyclosed by means of a spring surrounding the stem of each valve and whichare opened and closed in properly timed relation for the intake,compression, firing, and exhaust operations.

For the purpose of opening the valves, there is provided a tappet whichengages the end of the valve stemin each case and which is actuated by acam shaft so as to effect such opening of the intake and. exhaust valvesin proper sequence;

but also a certain amount of noise.

Also, such improper engagement between the tappet and the valve stemresults in undue wear of these parts as well as the valves and valvesets themselves; that is, any failure of the tappet to open the valvebecause of lack of proper operative engagement between these parts mightresult in the valve sticking to its seat, and failure to permit properintake and exhaust of the gases means failure to operate in an efficientmanner and hence loss of power and smooth running of the engine.

The present invention contemplates the relief of such conditions asabove briefly outlined and in a general way this invention consists inthe provision of an automatically adjustable tappet which is adapted tocompensate for and overcome any lack of proper adjustment and engagementbetween the tappet and valve stem as might otherwise occur.

gardless of in spite of any sticking of the any wear between the partsand also valve or other abnormal condition which might otherwise prevailand prevent eflicient operation. I

' The present invention is so devised that the automatic contraction andextension of the tappet will be efiected in a gradual manner so as toavoid any undue clash and wear between the parts.

Another object consists in devising such an automatically adjustabletappet which can be regarded as a complete unitwhich is capable of beinginstalled in an internal combustion engine without requiringmodification of the other parts.

A further object consists in providing such a device which canbemanufactured in'a comparatively simple manner and hence sold at acomparatively low price so as to render the same practical in everyrespect.

Other objects will be apparent from the fol-. lowing description andclaims when considered together with the accompanying drawing. 7

Fig. l is avertical sectional view illustratingthe structure andassembly of my improved form of tappet; I

' Fig.- 2 is a transverse sectional view taken on line 22 of Fig. 1; and

Fig. 3 is a vertical sectional view taken on line 3-3 of Fig. 1. Inthepresent illustration, there is indicated a valve l which is ofconventional form and which is arranged in the usual manner so as toclose upon the valve seat 2 provided upon the engine block 3. The valveI has the valve stem 4 surrounded by the coil spring 5 which has its oneend abutting the engine block while its other end engages the flangedmember 6 which is se-. cured near the lower end of the valve stem 4 soas to normally force the valve I to closed engagement with the valveseat 2. The lower end of the valve stem l, as usual, extends beyond theflanged members 6 so as to provide the lower projecting end portion 4for engagement by the upper end of the tappet. As above stated, theconstruction thus far described is of conventional form, as is also thecam shaft 1 and the cams 8 provided thereupon; it being understoodthatthe cam shaft is operated in the same manner as is already well known tothose skilled in theart.

In my present improved form of invention, the tappet comprises thecasing 9 which is flanged at its lower end 9 for engagement by the cam 8of the cam shaft. The casing 9 is hollowed-out throughout the upperportion thereof so as to receive with a drive fit the upper part I!)which has .the lower portion ll extending within the hollowed-outportion of the casing 9. Both the I formed with squared surfaces.

casing 9 and the upper part I are of cylindrical form as well as thelower portion II which fits within the casing 9. Thus, the parts 9 and I0 are secured together and may be considered as one and the same partwhich may be formed as a single integral member.

The lower extending portion I I is also hollowedout with a cylindricalwell adapted to receive and accommodate the coil spring I2 which restsin the bottom of the hollowed-out portion II while the upper end thereofhas bearing engagement with the lower end of the wedge member I3. Thewedge member I3 is also of cylindrical form and is provided at its upperside with an inclined surface extending approximately at an angle of 45,as indicated in the drawing. There is provided a companion wedge memberI4 which is also of cylindrical form and whichhas its lower sideprovided with a corresponding, inclined surface which is adapted toengage the inclined surface of the companion member l3. The inclinedengaging surfaces of the companion members I3 and I4 are of a flat orplain form sothat there will not be permitted any relativeturningmovement between these companion members. The companion member I3 ispractically co-terminous with the end portion I I and the lower part ofthe member I4 extends within the well portion II, while the upper endthereof projects upwardly into the enlarged upper portion of the part II), as clearly indicated in Fig. 1. 7

It will be observed that the companionmembers I3 and I4 are soconstructed that when they are in full engagement, as illustrated inFig. 1, there is still space allowed between the extreme upper end ofthe companion member I3 and the corresponding part of the member I4 andalso between theextreme lower end of the member I4 and the correspondingpart of the companion member I3. This arrangement insures effectivefrictional engagement between these members, as will be more fullyunderstood. It is to be understood also that the lower end of the memberI3 and the upper end of the member I4 are both Thus, these two companionmembers I3 and I 4 may be regarded as duplicates.

The upper squared end of the member I4 is adapted to engage the underside of a shoe I5 which has its upper surface curved, as indicated at I5so as to afford seating engagement for the eccentric member I6. Themember I6 has its stub shaft I1 mounted eccentrically with respectthereto and also to one side of the longitudinal axis through the tappetassembly, as clearly indicated in Fig. 1, the shaft I! being mounted inthe block I8 which is positioned within the upper enlarged hollowportion of the part IO. The bearing member I8 may rest upon a washer I8which is of annular form and through which the companion members I3 andI4 extend.

The shoe I9,,which is a duplicate of the shoe I8, is positioned abovethe eccentric member I6 so as to afford seating engagement therefor withthe curved surface I9 of this shoe. It should be explained that the shoeI8 is separate from the member and merely has seating engagementthereupon so as to be free for a certain degree of lateral movement asis true also of the upper shoe I9, such lateral movement being caused byactuation of the eccentric I 6.

Engaging over the upper fiat side of the shoe I9, there is provided thecap member 29 which has depending, annular llangeZD extending withfrictional en agement within the upper end of upper part ID. The upper,outer surface of the member is adapted for contactual engagement withthe lower projecting portion 4 of the valve stem.

The several parts of the present improved form of tappet are soconstructed and arranged in assembly thatthere is afforded not only thecompression of the spring I2 but also the frictional engagement betweenthe companion members I3 and I4 themselves over their engaging, inclinedsurfaces as well as between the cylindrical surfaces thereof and theengaging inner surface of the well portion II. There is furtherfrictional engagement afforded between the outer surface of theeccentric I6 and the correspondingly curved engaging surfaces of theshoes I5 and I9. Furthermore, frictional engagement is provided betweenthe flange 20 and the inner surface of the upper end portion of the partI 8 within which this flange engages and is adapted for movement. Also,by virtue of the engagement between the upper end of the member I4 andthe lower surface of the shoe I 5, as well as between the upper surfaceof the shoe I 9 and the inner under-surface of the member 20, there willbe afforded a still further degree of friction.

The friction above referred to as being afforded between the severalparts of my present tappet assembly, serves as a means of resistancewhich is of such degree as to prevent sudden contracting movementbetween the parts, but at the same time there will be permitted gradualcontraction in an effective manner for the purpose intended. It is to beunderstood also that the spring I2, although of comparatively inferiorstrength, may be relied upon to gradually and effectively causeautomatic extension between the parts and thus overcome the frictiontherebetween so as to produce the desired extension of the tappet at thetime required.

As indicated in the drawing, the spring I2 is ofcomparatively smallersize and less strength than, the spring 5. Assuming, for instance, thatthe spring 5 has a strength of approximately eighty (80) pounds, thespring I2 in my present improved assembly may be of only approximatelyten (10) pounds. However, the aggregate resistance offered by thecombined factors of the spring I2 and the friction between the severalparts, as above referred to, is somewhat in excess of the degree ofresistance offered by the spring 5. Thus, upon actuation of the presenttappet assembly by the cam shaft, this combined resistance offeredby thetappet will serve efficiently to overcome the resistance of the spring 5so as 4 to raise the valve from its seat.

It should be explained also that the degree of rotary movement of theeccentric I6 about the axis I! is, in the present form of device,approximately ninety degrees (90) and, as will be seen from the verynature of the eccentric, the degree of resistance induced therebythrough the frictional engagement thereof with the shoes I5 and I9 willbe gradual. The practical effect of such manner of operation is that theautomatic adjustment of the tappet assembly in either direction isgradual so as to produce a quiet and effective operation.

Upon installation of the present tappet assembly and during normaloperation of the same, the spring I2 will be placed and maintained under'a certain degree of compression by engagement of the tappet with thevalve stem. This compression of the spring 52 is constant andsubstantially uniform and, as before stated, the

Cal

combined resistance offered by the spring l2 and the frictionalresistance between the other parts is sufficient to cause opening of thevalve. The position and condition of the several parts of the presentassembly, as indicated in Fig. 1, correspond to normal operation, andthese parts all maintain substantially the same position and conditionthroughout normal opening and closing movements of the valve, the entiretappet assembly functioning as a unit. It is to be understood, ofcourse, that during such normal operation, the upper and. lower ends ofthe tappet are in constantcontactual engagement with the end portion 4of the valve stem and the cam of the cam shaft, respectively.

If, however, for any reason such, for instance, as the sticking oi thevalve stem in raised or open position, or wear between the parts so asto create what would otherwise be a gap between the upper end of thetappet and the lower end of the valve stem, then the automaticadjustment of the tappet assembly is called into play.

Let us consider first the possible wear between the lower end of thevalve stem and the upper end of the tappet which, as is well known,would ordinarily cause a gap with resultant noise and lack of ehiciencyin the operation of the valve. Under such condition, the present tappetassembly will automatically adjust itself so as to take up such wear andto always maintain contactual engagement between the upper end of thetappet and the lower end of thevalve stem. In other words, any such wearwhich would ordinarily cause a gap between these parts will becompensated for by the automatic extension which will be produced by theforce of the spring l2 between the extensible parts of the tappetassembly; and, as before explained, such extension between the parts ofthe tappet will be gradual by virtue of the frictional engagement andthe action of the eccentric 16. According to Fig. 1 of the drawing withthe parts in position as therein illustrated, the expanding or extendingaction of the spring IE will cause the eccentric 16 to turn in acounter-clockwise direction, and such operation of the eccentric I6 willproduce a gradual movement and friction between the parts.

Assuming now that the valve stem, because of sticking, has caused thevalve to remain in open position, ordinarily such condition would resultin a decided gap between the lower end of the valve stem and the upperend of the tappet, with the objectionable result already referred to.With the present form of device, the tappet will automatically extenditself by virtue of the spring l2 so as to gradually take up what wouldotherwise result in such a gap. In this case, as in the other case abovesupposed, the extending action between the parts of the tappet will begradual and the danger of any such gap will be obviated. That is, solong as the valve stem remains in abnormal raised position, the tappetassembly will continue in extended condition so as to at all timesmaintain contactual engagement between the upper end of the tappet andthe lower end of the valve stem. Continued operation of the cam shaftand engagement of the cam with the lower end of the tappet, although notefiective in producing normal operation of the valve so long as thevalve remains stuck in open position, yet will be permitted during suchabnormal position of the valve, and continued engagement of the cam withthe tappet will cause more or less compression of the spring [2 whichwill thereby absorb such motion of the cam shaft until it again becomeseffective for normal operation of the valve. Furthermore, since suchautomatic extension of the tappet will compensate for and overcome anysuch gap which might be caused, even by such abnormal sticking of thevalve stem in raised position, there is thereby always maintained aconstant contactual means of engagement between the tappet and the valvestem, and the intermittent engagement of the cam with the tappet willtransmit therethrough to the valve stem a certain degree of force whichis calculated to assist in overcoming the sticking of the valve stem.

Then upon release of the sticking valve stem with the aid of the spring5, the parts may again return to normal condition, and, as alreadyindicated, the contracting movement between the parts of the presenttappet assembly will be gradual by virtue of the combined component ofresistance offered by the frictional engagement between the severalparts as well as the force of the spring l2. This, under such conditionalso there is prevented any sudden movement of or between the parts andthus there is insured smooth and effective engagement and operation. Itis understood, that uponrelease of a sticking valve stem so as to permitcontracting movement of the tappet, the eccentric I6 will be moved in aclockwise direction, as viewed in Fig. 1. During such automaticadjustment between the parts, there will result also the same gradualand progressive increase of friction between the parts as alreadyexplained, and the spring l2 will again be placed under increasedcompression so as to assume condition for normal operation in the manneralready explained.

With the present invention, there is obviated the necessity of manuallyadjusting the tappet from time to time as is now required with thepresent form of construction and a further ad; vantage consists in theelimination of noise be tween the parts. Furthermore, the present devicemakes possible a more eificient operation, as will be obvious to thosewho are skilled in the art. Finally, the structure contemplated by thepresent invention is of a comparatively simple nature, is calculated tohave longer life without renewal of parts, and may be manufactured andsold at such a price as to encourage universal adoption.

Other advantages will be obvious to those who are skilled in the art towhich the present invention relates.

What I claim is:

1. In a tappet assembly, the combination of a valve adapted to normallyoccupy closed position, a tappet comprising a plurality oflongitudinally extensible, frictionally engaging parts with resilientmeans operatively associated therewith so as to permit contraction andeffect automatic extension of the same respectively, means having asurface of regular curvature operatable as an eccentric about a centerand having operative engagement with said parts for increasing thedegree of friction therebetween, and means for actuating the tappet soas to open the valve and permit closing thereof, whereby there isobtained automatic adjustment of the tappet so as to maintain normaloperative engagement of the tappet with the valve stem.

2. In a tappet assembly, the combination of a valve adapted to normallyoccupy closed position, a tappet comprising a plurality oflongitudinally extensible, frictionally engaging parts and resilientmeans operatively associated therewith, said parts including companionmembers having interengaging inclined friction faces, the saidfrictional parts and resilient means being so co-related that there ispermitted and effected gradual movement betweensaid parts in contractionand automatic extension of the same respectively, and means foractuating the tappet so as to open the valve and permit closing thereof,whereby there is obtained automatic and gradual adjustment of thelongitudinally extensible parts so as to maintain normal operativeengagement of the tappet with the valve stem.

3. In a tappet assembly, the combination of a valve adapted to normallyoccupy closed position, a tappet comprising a plurality oflongitudinally extensible, frictionally engaging parts and resilientmeans operatively associated therewith, said parts including companionmembers havmg interengaging inclined friction faces, the said frictionalparts and resilient means being so co-related that there is permittedand effected gradual movement between said parts in contraction andautomatic extension of the same re spectively, means for actuating thetappet so as to open the valve and permit closing thereof, and eccentricmeans having a surface of regular curvature and having operativeengagement with said parts so as to be actuated by extension andcontraction of the tappet for increasing the degree of frictionalengagement between the parts of the tappet, whereby there is obtainedautomatic and gradual adjustment of the tappet so as to maintain normaloperative engagement of the tappet with the valve stem.

4. In a tappet assembly, the combination of a valve adapted to normallyoccupy closed position, a tappet comprising a plurality oflongitudinally extensible, frictionally engaging parts with re silientmeans operatively associated therewith, said parts including companionmembers having interengaging inclined friction faces, the saidfrictional parts and resilient means being so co-related that there ispermitted and effected gradual movement between said parts incontraction and automatic extension of the same respectively, means foractuating the tappet so as to open the valve and permit closing thereof,and means including an eccentric having a surface of regular curvatureand friction shoes adapted for engagement thereby, said means havingoperative engagement with said parts and being actuated by extension andcontraction of the tappet for increasing the degree of frictionalengagement between the parts of the tappet, whereby there is obtainedautomatic and gradual adjustment of the tappet so as to maintain normaloperative engagement of the tappet with the valve stem.

5. An automatically adjustable tappet comprising a casing having ahollow Well portion provided therein, a coil spring in said well,inversely arranged, duplicate wedge members having frictional slidingengagement with the inner surface of said well portion and havinginterengaging inclined faces, one of said wedge members engaging the endof said spring, a pair of friction shoes having oppositely disposedcurved surfaces, an eccentric having frictional engagement between thecurved surfaces of said shoes, the under side of the lower shoe engagingthe end of the other of said Wedge members, a cap member having slidableengagement with the inner surface of said casing and having its undersurface in engagement with the upper side of said upper shoe, said partsbeing so constructed and arranged that the outer surface of said capmember may engage the end of a valve stem and the opposite end of saidcasing may be engaged by the cam of a cam shaft, and there may beautomatically effected gradual contraction and extension of the tappetin accordance with the condition of valve stem.

STEPHEN JENCICK.

